Process for oxidizing olefins using hydrocarbon soluble phosphorus modified molybdenum catalysts

ABSTRACT

Stable, homogeneous phosphorus-modified molybdenum catalysts are prepared by incorporating phosphorus ligands into molybdenum compounds. The molybdenum compounds are prepared by reacting an ammonia-containing molybdate with a hydroxy compound, for example, an organic primary or secondary alcohol, a glycol or a phenol. The hydrocarbon-soluble phosphorus-modified molybdenum solutions are useful as homogeneous oxidation catalysts, particularly for the oxidation of olefins to olefin oxides. Olefin oxides are useful in the manufacture of non-toxic antifreeze, urethane-grade polyols and many other applications. The catalysts of the invention may also be used as metal-plating solutions, lubricant additives, pigments, ammoxidation catalysts, printing inks, or solution components for organic laser devices. They may also be used as catalysts or co-catalysts for various polymerization processes, such as homopolymerization of isocyanates, isocyanate-polyol reactions, or olefin oxide polymerization reactions.

avitt ten [19] PROCESS FOR OXIDIZTNG OLEFINS USllNG HYDROCARBON SOLUBLEPHOSPHORUS MODllFllED MOLYBDENUM CATALYSTS [75] Inventor: Stanley BruceCavitt, Austin, Tex.

[73] Assignee: Jefferson Chemical Company, llnc.,

Houston, Tex.

22 Filed: July 26,1973

21 Appl. No.: 382,918

Related US. Application Data [62] Division at Ser. No. 102,138, Dec. 28,1970, Pat. No.

Primary Examiner-Norma S. Milestone Attorney, Agent, 0r'FirmJames L.Bailey; John R. Kirk, Jr.

[5 7] ABSTRACT Stable, homogeneous phosphorus-modified molybdenumcatalysts are prepared by incorporating phosphorus ligands intomolybdenum compounds. The molybdenum compounds are prepared by reactingan ammonia-containing molybdate with a hydroxy compound, for example, anorganic primary or secondary alcohol, a glycol or a phenol. Thehydrocarbonsoluble phosphorus-modified molybdenum solutions are usefulas homogeneous oxidation catalysts, particularly for the oxidation ofolefins to olefin oxides. Olefin oxides are useful in the manufacture ofnon-toxic antifreeze, urethane-grade polyols and many otherapplications. The catalysts of the invention may also be used asmetal-plating solutions, lubricant additives, pigments, ammoxidationcatalysts, printing inks, or solution components for organic laserdevices. They may also be used as catalysts or co-catalysts for variouspolymerization processes, such as homopolymerization of isocyanates,isocyanate-polyol reactions, or olefin oxide polymerization reactions.

5 Claims, N0 Drawings CROSS REFERENCE TO RELATED APPLICATION This is adivision, of application Ser. No. 102,138, filed Dec. 28, 1970 and nowUS. Pat. No. 3,784,482.

My co-pending application entitled Hydrocarbon Soluble MolybdenumCatalysts," Ser. No. 102,227, filed of even date with the aforesaidapplication Ser. No. 102,138 teaches the synthesis of hydrocarbonsolublemolybdenum catalysts prepared by reacting an ammonia-containingmolybdate with a hydroxy compound. The compounds of my copendingapplication are incorporated with phosphorus ligands to prepare thecatalysts of this invention.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTIONPhosphorus-molybdenum-hydroxy compound catalysts are prepared withphosphorus compounds capable of reacting with hydroxy compounds. Thephosphorusmodified molybdenum catalysts are synthesized by incorporatingthe phosphorus ligand with an ammoniacontaining molybdate and a hydroxycompound, for example, an organic primary or secondary alcohol, a glycolor a phenol. These phosphorus-modified molybdenum catalysts of theinvention can be preoxidized for better effectiveness as epoxidationcatalysts. The invent-ion includes the catalysts prepared by thisprocess and the use of the catalysts for the oxidation of olefins toolefin oxides.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention relates to thesynthesis of phosphorusmodified molybdenum catalysts. To prepare thecatalysts, phosphorus ligands are reacted with an ammoniacontainingmolybdate and a hydroxy compound. It is preferred to react thephosphorusligand with hydro-' phosphorus catalysts can be preoxidized for bettereffectiveness as epoxidation catalysts.

Conditions necessary to react the phosphorus com pounds may range fromabout room temperature to several hundred degrees and from about 15minutes to as much as 10 hours.

The following examples illustrate my invention in more detail but arenot intended to limit the scope of the invention. Examples 1-5illustrate the synthesis of several catalysts of the invention. Examples6 and 7 illustrate the preparation of an olefin oxide using thecatalysts of the invention.

EXAMPLE 1 Preparation of Phosphorus Molybdenum Decyl Alcohol Catalyst Toa 500 ml. distilling flask equipped with a magnetic stirring bar,thermometer, and foam trap were added g. of about 5% molybdenum (as amolybdic acid decyl alcohol reaction product) and 14 g. of granularphosphorus pentoxide. The mixture was heated under aspirator vacuum(air-bleed regulated) at about 150C. until all of the solid dissolved.Then 100 g. of decyl alcohol was added (the solution changed from greento brown color) and the flask and contents were reheated to 140-'150C.for one hour with slow re moval of water and lights and alcohol(solution color changed back to green). Most of the excess alcohol wasthen removed under full aspirator vacuum, after which the liquidconcentrate was heated on a water bath 100C.) under full pump vacuumusing a rotary evaporator to remove the remainder of the alcohol. Therewas recovered 88 g. of a viscous, green solution; no solid residues wereobserved. The 88 g. of green concentrate was then diluted with 500 ml.of chlorobenzene and oxidized in a stream of oxygen for one-half hour atC. The solution remained green throughout the oxidation period; noresidues were formed. After concentrating the oxidized molybdenumsolution on a steam bath under aspirator vacuum, there was obtained 225g. of dark, yellow-green solution which contained 1.4 wt. molybdenum andhad a phosphorus/- molybdenum g. atom weight ratio of about 5.25/1.

EXAMPLE 2 Preparation of Phosphorus Molybdenum lsononyl AlcoholCatalysts To a 500 ml. distilling flask equipped with a magneticstirring bar, thermometer, and foam trap were added 100 g. of 4%molybdenum (as a molybdic acid isononyl alcohol reaction product) and3.0 g. of granular phosphorus pentoxide. The mixture was heated underaspirator vacuum at reflux temperature until the solid dissolved and alllights were removed, then most of the excess alcohol was removed. Theconcentrated solution was then transferred to a rotary evaporator andheated on a water bath under full pump vacuum until all excess alcoholwas removed. The 28 g. of liquid concentrate obtained was then dilutedwith 500 ml. of chlorobenzene and oxidized under the usual conditionsfor one hour. giving a very deep turquoise-blue solution. Afterconcentrating on a steam bath under aspirator vacuum. there was obtained239 g. of blue-green solution containing 1.6 wt. molybdenum.

EXAMPLE 3 Preparation of Phosphorus Molybdenum lsononyl Alcohol CatalystThis experiment was performed in the same manner as example 2, exceptthat a fresh batch of molybdic acidisononyl alcohol reaction product wasemployed along with 6.0 g. of phosphorus pentoxide. After workup, the 37g. of concentrated solution obtained was diluted with chlorobenzene andoxidized by the usual procedure to give, after workup, a very deep bluesolution containing 2.0 wt. molybdenum. This solution was furtherconcentrated to give a slightly viscous, deep-blue solution containingabout 10% molybdenum. The phosphorus-modified molybdenum catalysts of myinvention useful in oxidation of olefins can be preoxidized in thepresence or absence of alcohol used in the catalyst synthesis.

EXAMPLE 4 Preparation of Phosphorus Molybdenum 2-Ethyl- 1,3-HexyleneGlycol Catalyst This experiment was performed in the same manner asexample 2, except 50 g. of 6.3 wt. molybdenum (as a molybdic acid2-ethyl-l,3-hexanediol reaction product) and 4.6 g. of phosphoruspentoxide were employed. The final oxidized solution (111 g.) was a deepblue color and contained about 2.7 wt. molybdenum.

EXAMPLE 5 Preparation of Phosphorus Molybdenum Isononyl Alcohol CatalystThis experiment was performed in the same manner as example 2, except100 g. of 4% molybdenum (as a molybdic acid isononyl alcohol reactionproduct) and 9.0 g. of phosphorus pentoxide were employed. The finaloxidized solution was an emerald green color, weighed 100 g., andcontained about 3.5 wt. 70 molybdenum.

EXAMPLE 6 Oxidation of Propylene to Propylene Oxide Using APhosphorus-Containing Molybdic Acid-n-Decanol Reaction Product Theapparatus used for this oxidation experiment was a stirred,ceramic-lined, 500 ml. autoclave. Chlorobenzene solvent containing 28.5ppm. molybdenum (as a phosphorus-containing, oxidized molybdicacid-ndecanol reaction product) was premixed with oxygen and fed intothe autoclave at two points: a connection, bottom center. where thisfeed was mixed with propylene, and a dip tube extending about half-wayto the bottom of the autoclave. The autoclave was fitted with a coolingcoil to provide close temperature control, and was equipped with amechanical stirrer with three sets of propellers on the shaft. A productwithdrawal tube at the top of the autoclave allowed the product to exitto a cooling coil and then through a back-pressure regulator to agas-liquid separator where the off-gas was metered and sampled and theliquid product was retained for weighing and sampling. Thesolvent-filled reactor was heated to reaction temperature (250C.) andpropylene was fed to the reactor for [-15 minutes before the oxygen wasturned on. After the initial exotherm, about to 1 hour prerun, a steadystate was achieved, the product was collected, and the off-gas wassampled. The feed rates for the reaction were as follows: chlorobenzene,45.8 lbs./hr.; propylene, 8.8 lbs./hr.; oxygen, 564 g./hr. The holdingtime was 1.2 minutes.

The yield of propylene oxide by chromatography, allowing for residuesformed, was 48 mol and the conversion based on propylene was 13 mol Theresidues/oxide wt. ratio was 0.34 and the oxide/acids wt. ratio was 6.5.The soluble molybdenum recovery was 97% of theory.

EXAMPLE 7 Oxidation of Propylene to Propylene Oxide Using APhosphorus-Containing Molybdic Acid Tetrahydrofurfuryl Alcohol ReactionProduct The apparatus used for this oxidation experiment was a stirred,ceramic-lined, 500 ml. autoclave. Chlorobenzene solvent containing 26.8ppm molybdenum (as a phosphorus-containing, oxidized molybdicacid-tetrahydrofurfuryl alcohol reaction product) was premixed withoxygen and fed into the autoclave at two points: a connection, bottomcenter, where this feed was mixed with propylene, and a dip tubeextending about half-way to the bottom of the autoclave. The autoclavewas fitted with a cooling coil to provide close temperature control, andwas equipped with a mechanical stirrer with three sets of propellers onthe shaft. A product withdrawal tube at the top of the autoclave allowedthe product to exit to a cooling coil and then through a back-pressureregulator to a gas-liquid separator where the off-gas was metered andsampled and the liquid product was retained for weighing and sampling.The solvent-filled reactor was heated to reaction temperature (230C) andpropylene was fed to the reactor for lO-l5 minutes before the oxygen wasturned on. After the initial exotherm, about V2 to 1 hour prerun, asteady state was achieved, the product was collected, and the off-gaswas sampled. The feed rates for the reaction were as follows:chlorobenzene, 45.2 lbs./hr.; propylene, 8.44 lbs./hr.; oxygen, 564g./hr. The holding time was 1.2 minutes. The yield of propylene oxide bychromatography allowing for residues formed, was 59 mol and theconversion based on propylene was 12 mol The residues/oxide wt. ratiowas ().l6, and the oxide/acids wt. ratio was 48/1. The solublemolybdenum recovery was 86.5% of theory.

Effective amounts of catalyst for the oxidation of olefins to olefinoxides range from about 5 to 1,000 parts per million (ppm) based on thetotal feedstock. Preferred ranges are between 10 and 100 ppm.

The hydrocarbon-soluble phosphorus-modified molybdenum solutions of theinvention are useful as homogeneous oxidation catalysts, particularlyfor the oxidation of olefins to olefin oxides. They are also of value asmetal plating solutions, lubricant additives, ammoxidation catalysts,printing inks, pigments, or solution components for organic laserdevices. The compounds of the invention may be used as catalysts orco-catalysts for various polymerization processes such ashomopolymerization of isocyanates, isocyanate-polyol reactions or olefinoxide polymerization reactions. Olefin oxides are useful in themanufacture of non-toxic antifreeze, urethane-grade polyols and manyother applications.

Any temperature and time combination can be used to prepare thecatalysts of the invention which will result in dissolution of the basicmolybdenum compound. The preferred conditions are temperatures of about100 to 200C. and reaction times of about 1 to 4 hours.

Examples of the ammonia-containing molybdates useful in the inventionare ammonium paramolybdate or 85% molybdic acid which contains about 85%paramolybdate.

The hydroxy compounds useful in the synthesis of catalysts of theinvention are, for example, primary or secondary alcohols or glycolscontaining 3 to 30 carbon atoms, or phenols. The alcohols may containolefinic groups or saturated ether groups. The alcohols may be purecompounds or mixtures of isomers. Mixtures of isomers, particularlythose of highly branched or iso alcohols, are usually preferred. Thealcohols include primary and secondary linear, branched, alicyclic,aliphatic, and arylaliphatic alcohols, including those with unsaturatedolefinic groups or cyclic or aliphatic ether groups. Further examples ofhydroxy compounds useful in the synthesis of catalysts of the inventionare 5-norbornene-2-methanol, 2,2,4-trimethyl-l ,3- pentanediol, nonylphenol, 3,5,5-trimethyl-l-hexanol, methoxyethanol, 1,3-propylene glycoland 1,2- propylene glycol.

Gram-atom weight ratios of phosphorus to molybdenum can range from0.25:1 to 30:1.

Comparable results to those in the examples, supra, are obtained insynthesizing other catalysts of the invention and in the synthesis ofolefin oxides from olefins, for example ethylene, propylene, butylene orisobutylene or higher olefins, using the catalysts of my invention.

Having thus described my invention,

1 claim:

1. In a liquid phase process for oxidizing olefins to olefin oxideswhereby the olefin is heated with oxygen in the presence of an oxidationcatalyst and an organic solvent in liquid phase at a temperaturesufficient to promote the oxidation reaction, the improvement whichcomprises oxidizing the olefin in the presence of an effective amount ofa hydrocarbon-soluble phosphorus molybdenum-hydroxy compound catalystprepared by heating a phosphorus compound (A) with ammonium molybdate(B) and a hydroxy compound (C) containing from 3 to 30 carbon atoms permolecule selected from the group consisting of an organic hydrocarbonprimary alcohol, organic hydrocarbon secondary alcohol, a phenol and analiphatic hydrocarbyl glycol to a temperature which dissolves saidammonium molybdate (B) wherein said phosphorus compound (A) is onecapable of reacting under said conditions with said hydroxy compound (C)selected from the group consisting of phosphorus pentoxide, phosphorustrichloride, phosphorus pentasulfide, phosphorus oxyehloride, phosphorussulfochloride, phosphoric acid and phosphorous acid and wherein thehydroxy con centration of (C) is in excess of the molybdateconcentration of (B) and wherein the gram-atom weight ratio ofphosphorus of said phosphorus compound (A) to molybdenum of saidammonium molybdate (B) is in the range from .25:1 to 30:1.

2. A process according to claim 1 wherein thephosphorus-molybdenum-hydroxy compound product is preoxidized byrefluxing said product in the presence of oxygen before it is used tooxidize the olefin.

3. A process according to claim 1 wherein the phosphorus compound (A) isphosphorus pentoxide.

4. A process according to claim 1 wherein the olefin is propylene.

5. A process according to claim 1 wherein the hydrocarbon-solublecompound catalyst is present in an amount from about 5 to 1,000 partsper million based on the total olefin feedstock.

phosphorus-molybdenum-hydroxy

1. IN A LIQUID PHASE PROCESS FOR OXIDIZING OLEFINS TO OLEFIN OXIDESWHEREBY THE OLEFIN IS HEATED WITH OXYGEN IN THE PRESENCE OF AN OXIDATIONCATALYST AND AN ORGANIC SOLVENT IN LIQUID PHASE AT A TEMPERATURESUFFICIENT TO PROMOTE THE OXIDATION REACTION, THE IMPROVEMENT WHICHCOMPRISES OXIDIZING THE OLEFIN IN THE PRESENCE OF AN EFFECTIVE AMOUNT OFA HYDROCARBON-SOLUBLE PHOSPHOROUS MOLYBDENUMHYDROXY COMPOUND CATALYSTPREPARED BY HEATING A PHOSPHOROUS COMPOUND (A) WITH AMMONIUM MOLYBDATE(B) AND A HYDROXY COMPOUND (C) CONTAINING FROM 3 TO 30 CARBON ATOMS PERMOLECULE SELECTED FROM THE GROUP CONSISTING OF AN ORGANIC HYDROCARBONPRIMARY ALCOHOL, ORGANIC HYDROCARBON SECONDARY ALCOHOL, A PHENOL AND ANALIPHATIC HYDROCARBYL GLYCOL TO A TEMPERATURE WHICH DISSOLVES SAIDAMMONIUM MOLYBDATE (B) WHEREIN SAID PHOSPHOROUS COMPOUND (A) IS ONECAPABLE OF REACTING UNDER SAID CONDITIONS WITH SAID HYDROXY COMPOUND (C)SELECTED FROM THE GROUP CONSISTING OF PHOSPHOROUS PENTOXIDE, PHOSPHORUSTRICHLORIDE, PHOSPHORUS PENTASULFIDE, PHOSPHORUS OXYCHLORIDE, PHOSPHORUSSULFOCHLORIDE, PHOSPHORIC ACID AND PHOSPHOROUS ACID AND WHEREIN THEHYDROXY CONCENTRATION OF (C) IS IN EXCESS OF THE MOLYBDATE CONCENTRATIONOF (B) AND WHEREIN THE GRAM-ATOM WEIGHT RATIO OF PHOSPHORUS OF SAIDPHOSPHORUS COMPOUND (A) TO MOLYBDENUM OF SAID AMMONIUM MOLYBDATE (B) ISIN THE RANGE FROM .25:1 TO 30:1.
 2. A process according to claim 1wherein the phosphorus-molybdenum-hydroxy compound product ispreoxidized by refluxing said product in the presence of oxygen beforeit is used to oxidize the olefin.
 3. A process according to claim 1wherein the phosphorus compound (A) is phosphorus pentoxide.
 4. Aprocess according to claim 1 wherein the olefin is propylene.
 5. Aprocess according to claim 1 wherein the hydrocarbon-solublephosphorus-molybdenum-hydroxy compound catalyst is present in an amountfrom about 5 to 1,000 parts per million based on the total olefinfeedstock.